Prior to the instant invention, molded egg cartons have been produced from molds so that the rim of the inverted dished cover and the rim of the cellular section and the hinged flap are generally in the same plane. An example of such a prior carton is illustrated in the U.S. Pat. No. to Reifers and Lord, 3,185,370. Such prior cartons are adapted for use in automated egg packing systems.
When cartons of this general character are produced, they are nested in stacks which are packaged for shipment to egg packers, who have the task of denesting each carton so that each carton may be presented to an egg loader and then to a carton closer, and finally, the loaded, closed egg cartons are then packed into egg cases for shipment to the supermarket.
Prior egg cartons in stacks have been separated from each other by denesting ledges located at or around the corners of the cover section and the corners of the cellular sections. Such stacks of egg cartons have been presented to denesting apparatus and have been separated automatically for replacement on conveyors to receive eggs from automated egg loaders. In such prior systems using such prior egg cartons, a certain amount of downtime has been experienced due to the difficulty in separating the end egg carton from the stack because of what has been characterized as "telescoping". This objectionable "telescoping" occurs when the cover section of one carton, or the cellular section of one carton, overrides or partially overrides the denesting ledge of the corresponding portion of the adjacent carton in the stack.
This "telescoping" may occur at the time of nesting of the cartons when the stack is produced, or it may occur in the packaged stack during the course of shipment to the egg packer, as some settling occurs in the stack during shipment by rail or truck, and a single stack of egg cartons in a single package may have one or more incidences of "telescoping".
With the advent of higher and higher speeds of molded egg carton production, and correspondingly, higher speeds of nesting or stacking, the chance for the incidence of "telescoping" to occur is markedly increased. This incidence of "telescoping" occuring at the time of stacking takes place when the molded carton is presented to the stack in somewhat imprecise relationship, or with a departure from absolute parallelism so that a carton then may "telescope" when pressure is applied to the stack in the course of the packaging of the stack. It is known that the height of a stack may decrease during the course of shipment to the egg packer and when this decrease in height occurs coincidently with the presence of a slightly cocked egg carton, then "telescoping" may occur.
When "telescoping" occurs and appears in the stack in the plant of the egg packer, and the egg packer loads a stack with one or more incidences of "telescoping" into his denesting apparatus, a jam will occur during the operation of the automatic equipment resulting in shutdown of the denesting machine, the empty carton take-away conveyor from the denesting machine, the automatic egg loader which serves to load the empty egg cartons, the automatic closer which closes the egg cartons, and the automatic egg case packer which packs the egg cases with closed and loaded egg cartons. Such shutdowns are costly and time consuming.